Printing telegraph apparatus



Aug. 15, 1944.

R. .D. SALMON PRINTING TELEGRAPH APPARATUS Filed MaI ch 4, 1945 Patented Aug. 15, 1944 2,356,092 PRINTING TELEGRAPHAPPARATUS Reginald Dennis Salmon, Croydon, England, as-

signorto Cree d and Company Limited, Croydon,

England, a British company Application March 4, 1943, Serial No. 477,925

In Great Britain March 31, 1942 Claims.

This invention relates to printing telegraph apparatus using a typewheel and to arrangements in such apparatus for closing an alarm circuit on receipt of a particular signal combination.

Arrangements for closing an alarm circuit on receipt of a particular signal combination are well known in printing telegraph receivers using type bars, and in such receivers the signal combina-' tion selects a particular bar for actuation in the same manner in which a type bar is selected. The actuation of the printing bail which follows then actuates the particular bar referred to in the same manner as it would have actuated a type bar if such had lected bar closes contacts in the circuit of an electrically operated alarm.

A similar manner of actuating contacts may also be used in those printing telegraph receivers equipped with typewheels in which a selector bar is selected to act as a stop in the path of the typewheel to arrest it in printing position, such, for example, as the receiver described in U. S. Re-issue No. 17,725' In telegraph receivers in which the typewheel shaft is progressively rotated by selected amounts in accordance with the nature of successive signal elements, such as those described in U. S. Specification No. 2,167,505 or British No. 473,614, there is a difficulty in carrying out a closure of the circuit of an electrically operated alarm in response to a received signal combination because the typewheel shaft passes through a given position when moving to selected positions other than that in which the alarm is to be given. In the receiver described in British Patent No. 473,614 for example, the typewheel is always returned to an initial position before being moved by a receiver signal combination, and if a contact operating arm were provided on the typewheel shaft or on a selectively positioned shaft that serves to position the typewheel, so as to close contacts when the typewheel or shaft is arrested in a selected position, such contacts would be momentarily closed for every received signal combination.

According to the present invention a printing telegraph receiver in which a typewheel is progressively rotated in accordance with the nature of successive signal elements, is characterized in that an electric alarm circuit is provided having a first pair of contacts adapted to be closed when a selecting shaft is in a given selected position and a second pair of contacts in series therewith adapted to be closed only after the said shaft has been brought into selected position.

been selected and the se- The nature of the invention willbe derstood from the following description of one embodiment thereof taken in conjunction with the accompanying drawing, whichisa perspective view of so much of the printing telegraph r ceiver described in British PatentNo. 550, l95 as is necessary for the understanding of the pres-1 ent invention.

The printing telegraph receiver are fixed, cams for -con-' trolling the sequence of operations of the re-" camsle'eve l on which ceiver and the printing and paper feeding operations. This cam sleeve l is, inwell known manner, clutched to a shaft continuously driven by an electric motor upon the receipt of the tart element of a code combination. The receiver I 2 mounted parallel to the cam sleeve l and adapted to be driven by means of a friction clutch by an electric motor. The typewheel I48 is mounted on a sleeve 6!] splined to shaft 2. The shaft2 is normally held stationary by means of a detent held against a stop arm thereon. Other detents cooperating'ivith rows of stops on the shaft 2 are normally out of the path of their rows of stops. These'detents are selectively actuated in "accordance with the code elements of a signal combination and any detent actuated into the path of its corresponding two of stops causes the withdrawal of any previously actuated detent whereby the shaft 2 is selectively allowed to be driven by means of the above mentioned friction clutch, and is arrested in a position characteristic of the received signal combination. Fixed to shaft 2 is a finger I03 which is adapted when the shaft 2 passes through or is arrested in a particular position to operate a lever I94, pivoted at 4, against the action of a spring 3. Actuation of lever I94 causes, through rod I05, closure of contacts I06 in the circuit of an electrically operated alarm 53. The alarm 53 is not, however, operated until a circuit is closed from one pole, of battery 55 through alarm 53, contacts I06 and contacts I513, back to the other pole of battery 55. Contacts It!!! are open during the movement of the shaft 2. When the selective movement of shaft 2 has come to an end a cam,3l on shaft I moves a cam lever 59 to cause an extension 58 thereof to move a lever 5| for a purpose explained in the above mentioned British patent, but of no importance for the present invention. Lever 5| rests against a pin 6 on a lever l0l and in moving rotates a lever llll, in an anti-clockwise direction about its pivot 5 against a spring 102 and thus closes contacts I00. Shaft I is shown in a position it ascomprises also a shaft better unsumes after it has moved from rest, but it comes to rest in a position in which the high part of the cam 3| is acting on lever 59 so that contacts I are closed. It will be seen therefore that if shaft 2 has been positioned in accordance with a particular alarm signal combination it comes to rest in a position in which contacts I06 are maintained closed whilst shaft I comes to rest in a position in which contacts I00 are maintained closed. Thus the circuit of alarm 53 is closed and remains closed until another signal combination is received. Should a, signal combination other 1 than that required to actuate the alarm bereceived arm I03 will act to close contacts I06 momentarily during the movement of the shaft 2 but at such time contacts I00 will not be closed. The shaft 2 will come to rest in a position other than that in which contacts I06 are kept closed.

and thus when contacts I00 are closed contacts I 06 are open. The alarm will thus not be actuated unless the desired signal combination is received. I

It is clear that the finger I 03 would equally well be mounted-upon the sleeve 60. This sleeve rotates with shaft 2 but is movable longitudinally of shaft 2 in response to shift signals. By mounting finger I03 on sleeve 60 and suitably positioning lever I04 it could be ensured that contacts I06 would not be closed in response to a signal combination unless it had been preceded by-a figure shift combination.

What is claimed is:

1. In a printing mechanism, an electrical alarm system responsive to special signals comprising a circuit including two separate actuating means and an alarm operative when said means are simultaneously actuated, printing means, aselector associated therewith, means adapted to operate one of said actuating means in predetermined positions of said selector corresponding to the special signals, synchronized signal responsive means for actuating said selector and means operative at the end of a selecting cycle of said selector for operating said second actuating means.

2. In a printing mechanism, an electrical alarm system as set forth in claim 1, in which said printing means includes a plurality of groups of printing elements and said selector includes means for shifting said groups of elements into and out of printing position and for simultaneously shifting said first operating means into and out of operative relation with its associated actuating means.

3. In a printing mechanism, an electrical alarm system responsive to special ignals comprising a circuit including two normally open contacts and an alarm operative when both of said contacts are closed, printing means, a rotary selector associated therewith, means adapted to close one of said contacts in predetermined positions of said selector corresponding to the special signals, signal responsive means for actuating said selector rotating in synchronism therewith, resetting means operative at the end of a selecting cycle of movement of said selector and means actuated by said resetting means at the end of said selecting'cycle but prior to the subsequent resetting cycle of movement of said selector, to close said second contact.

4. In a printing mechanism, an electrical alarm system responsive to special signals comprising a circuit including two normally open contacts and an alarm in series, a typewheel, a rotary selecting shaft connected to and operating said typewheel, a member on the shaft engaging one contact in certain shaft positions, arranged to close said contact in said positions, means for actuating said selecting shaft including a signal responsive cam shaft rotating in synchronism therewith, a resetting mechanism operative at the end of a selecting cycle of movement of said selecting shaft and a member actuated by said mechanism at the end of a selecting cycle of movement but prior to the subsequent resetting cycle of move ment to close said second contact.

5. In a printing mechanism, an electrical alarm system as set forth in claim 4, in which said typewheel has successive rows of type faces and said selecting shaft is provided with a longitudinally movable sleeve on which said typewhecl and finger are mounted, said finger being arranged to close its associated contact When a particular group of type faces in one row has been brought into printing position.

REGINALD DENNIS SALMON. 

